JP2006193015A - Tire pressure-adjusting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tire pressure-adjusting device capable of changing the proper value of the tire pressure in accordance with variables such as the vehicle speed, road conditions, etc. and of simplifying the constitution. <P>SOLUTION: Air filling of the tire is made using an air filling device, and if the tire pressure exceeds the target value (=Pset), the air is released through an air releasing passage by driving a valve with a small actuator installed on a transmitter. The pressure target value at this time is changed not only according to the user's request but also to variables such as the vehicle speed, road conditions, etc. Thereby the tire pressure can be adjusted by the transmitters mounted on the respective wheels and the air filling device, and also it is possible to change the pressure target value only by sending the signal exhibiting the tire pressure setting value Pset from a receiver to the transmitter. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a tire pressure adjusting device capable of adjusting a tire pressure so that the tire pressure becomes an appropriate pressure.

  2. Description of the Related Art Conventionally, a tire pressure adjusting device has been shown in which an air pump is attached to a wheel of a wheel, compressed air is generated by rotational energy of the tire, and the air pump is driven to fill the tire with air (for example, Patent Literature) 1 and Patent Document 2).

  In such a tire pressure adjusting device, the air pressure is prevented from being lowered by air filling with an air pump, and the air release passage is opened by moving the air release valve when the tire pressure exceeds a certain pressure. In this way, excessive air filling is prevented.

  In addition, a tire pressure adjusting device has been proposed in which a control unit provided on the vehicle body side sets an air pressure according to a variable such as a vehicle speed or a road condition and adjusts the air pressure (see, for example, Patent Document 3).

In this tire pressure adjusting device, a part for performing a series of controls is provided on the vehicle body side, and air is filled into the tire by an air compressor directly connected from the vehicle body side.
Japanese Patent No. 182436 JP 2004-114908 A Japanese Patent Laid-Open No. 2003-326928

  However, in the tire air pressure adjusting devices shown in Patent Document 1 and Patent Document 2, the air release valve opens the air release passage when the tire air pressure exceeds a certain pressure. The pressure becomes a constant value and cannot be changed. The appropriate pressure of the tire pressure varies depending on a change in temperature, a change in atmospheric pressure, a change in road surface condition, a difference in vehicle speed, and the like, and does not necessarily match the pressure at which the air is released. For this reason, there is a problem that the tire pressure cannot be maintained at an appropriate pressure.

  On the other hand, in the tire air pressure adjusting device shown in Patent Document 3, the tire air pressure is set according to variables such as the vehicle speed and the road condition, but a portion of the tire air pressure adjusting device that performs a series of controls is provided on the vehicle body side. Therefore, the structure of the tire pressure adjusting device becomes complicated, and there is a problem that it is difficult to mount on a general commercial vehicle.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a tire pressure adjusting device that can change the appropriate pressure of tire pressure according to variables such as vehicle speed and road conditions, and can simplify the configuration.

  In order to achieve the above object, according to the first aspect of the present invention, the transmitter (2) provided to each of the plurality of wheels (5a to 5d) is provided to each of the plurality of wheels (5a to 5d). A sensing unit (21) that outputs a detection signal corresponding to the air pressure in the tire and a detection signal from the sensing unit (21) are detected to detect the tire air pressure, and when the tire air pressure exceeds a target air pressure, A first control unit (22a) that generates an opening command signal, a first wireless unit (22b) that receives radio waves, and an air release command signal generated by the first control unit (22a) are driven and tires A small actuator (24) for releasing air from the inside to the outside. Further, the receiver (3) provided on the vehicle body (6) side determines a tire air pressure set value (Pset) for each of the plurality of wheels (5a to 5d), and a signal indicating the tire air pressure set value (Pset). And a second wireless unit (32a) that transmits radio waves toward the transmitter (2). The first control unit (22a) receives a signal indicating the tire air pressure setting value (Pset) output from the second control unit (32b) through the first and second radio units (22b, 32a), and the tire air pressure. The setting value (Pset) is set as the air pressure target value.

  As described above, the air pressure target value that the first control unit (22a) uses as the air release threshold value can be changed to the tire air pressure setting value (Pset) determined by the second control unit (32b). For this reason, an air pressure target value can be changed according to various requests.

  Further, since the air pressure target value can be changed simply by sending a signal indicating the tire air pressure setting value (Pset) from the transmitter, it is possible to provide a tire air pressure adjusting device that can simplify the configuration.

  For example, in the invention described in claim 2, the operation switch (4a) for generating a signal indicating the tire pressure desired by the user or a signal associated with the tire pressure is provided, and the operation switch (4a) generates the signal. The second control unit (32b) is input to the second control unit (32b) in the receiver (3), and the second control unit (32b) is operated by the user based on the signal generated by the operation switch (4a). It is characterized in that a desired tire air pressure is determined as a tire air pressure setting value (Pset).

  Thus, the tire pressure setting value (Pset) can be determined according to the user's request. For this reason, it can be set as the air pressure target value according to the user's request.

  Further, in the invention according to claim 3, the second control unit (32b) in the receiver (3) receives various types of information that may cause fluctuations in the appropriate tire pressure of each of the plurality of wheels (5a to 5d), The tire air pressure setting value (Pset) is determined on the basis of various information that can be a variation factor.

  In this way, the tire pressure set value (Pset) can be determined based on various information that can be a factor of fluctuation of the appropriate tire pressure. As a result, it is possible to appropriately change to an appropriate air pressure target value in consideration of a variation factor of the appropriate tire air pressure.

  In the invention according to claim 4, in the transmitter (2), the sensing unit (21) outputs a detection signal related to the temperature in the tire, and the first control unit (22a) The detection signal of the sensing unit (21) is signal-processed and stored in the transmission frame. Furthermore, the transmission frame is transmitted to the receiver (3) through the first radio unit (22b), and the receiver (3) receives the transmission frame through the second radio unit (32a). The tire pressure setting value (Pset) is corrected based on the detection signal corresponding to the temperature stored in the transmission frame in the second control unit (32b). The value is determined as a tire air pressure setting value (Pset).

  Thus, based on the detection signal corresponding to the temperature in the tire sent from the transmitter (2), the tire air pressure set value (Pset) is corrected, and the corrected value is used as the tire air pressure set value (Pset). ). Accordingly, it is possible to prevent the air from being excessively extracted with respect to the increase in air pressure due to the temperature rise based on Boyle Charles' law.

  In the invention according to claim 5, the second control unit (32b) uses a predetermined reference as the tire air pressure of the plurality of wheels (5a to 5d) based on the detection signal corresponding to the temperature stored in the transmission frame. The pressure converted into temperature is obtained, and if this pressure does not exceed the tire air pressure set value (Pset), an air pressure correction invalid signal is transmitted from the second control section (32b) through the second radio section (32a). The transmitter (2) is prohibited from driving the small actuator (24) to release air.

  Thus, the tire air pressure when converted into a predetermined reference temperature is obtained, and when this does not exceed the air pressure target value, the air pressure correction invalid signal is transmitted to prohibit the air release. The same effect can be obtained.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows the correspondence with the specific means as described in embodiment mentioned later.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

(First embodiment)
A first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the overall configuration of a tire pressure detecting device to which a tire pressure adjusting pressure reducing valve according to an embodiment of the present invention is applied. The upper direction in the drawing of FIG. 1 corresponds to the front of the vehicle 1, and the lower direction of the drawing corresponds to the rear of the vehicle 1. With reference to this figure, the tire pressure detecting device in the present embodiment will be described.

  As shown in FIG. 1, the tire air pressure detection device is attached to a vehicle 1 and includes a transmitter 2, a receiver 3, and a display 4.

  As shown in FIG. 1, the transmitter 2 is attached to each wheel 5 a to 5 d in the vehicle 1, and detects the air pressure of the tire attached to the wheels 5 a to 5 d and a detection signal indicating the detection result. Is stored in a transmission frame and transmitted.

  The receiver 3 is attached to the vehicle body 6 side of the vehicle 1 and receives a transmission frame transmitted from the transmitter 2 and performs various processes and calculations based on the detection signal stored therein. By doing so, the tire pressure is obtained. 2A and 2B show block configurations of the transmitter 2 and the receiver 3. Moreover, the schematic diagram of the wheels 5a-5d with which the transmitter 2 and the air filling apparatus 7 are provided in FIG. 3 is shown.

  As shown in FIG. 2A, the transmitter 2 includes a sensing unit 21, a microcomputer 22, an antenna 23, and a small actuator 24.

  The sensing unit 21 includes, for example, a diaphragm type pressure sensor and a temperature sensor, and outputs a detection signal corresponding to the tire pressure and a detection signal corresponding to the temperature.

  The microcomputer 22 is composed of a well-known computer having a CPU, ROM, RAM, I / O, and the like. Specifically, a control unit (first control unit) 22a and a radio unit 22b are provided, and predetermined processing is executed according to a program stored in the ROM.

  The control unit 22a receives the detection signal related to the tire pressure from the sensing unit 21, processes the signal and processes it as necessary, stores it in the transmission frame as data indicating the detection result, and then wirelessly transmits the transmission frame. This is sent to the unit 22b. The process of sending a signal to the wireless unit 22b is executed at predetermined intervals according to the program.

  Moreover, the control part 22a changes the target value of a tire pressure based on the tire pressure setting value sent from the receiver 3, as will be described later. And the control part 22a calculates | requires tire air pressure based on the detection signal regarding the tire air pressure from the sensing part 21, determines whether the obtained tire air pressure exceeds the set target value, and exceeds The small actuator 24 is driven.

  The radio unit 22 b functions as an output unit that transmits the transmission frame transmitted from the control unit 22 a to the receiver 3 through the antenna 23. The wireless unit 22b also functions as an input unit that receives radio waves received through the antenna 23 and sends a signal indicated by the radio waves to the control unit 22a.

  The antenna 23 is a transmission / reception antenna that functions as both a transmission antenna used for transmission of a transmission frame transmitted from the radio unit 22b and a reception antenna that receives radio waves transmitted from the receiver 3. Note that although the antenna 23 is configured as a transmission / reception antenna here, the transmission antenna and the reception antenna may be configured separately.

  The small actuator 24 is driven based on a control signal (air release command signal) from the control unit 22a. When the small actuator 24 is driven, as will be described later, a valve for controlling the opening and closing of the air release passage provided in the air valve to which the transmitter 2 is attached is driven. Thereby, the opening / closing of the air release passage is controlled, and when the tire air pressure exceeds the air pressure target value, the air release passage is opened by the valve to release air, and the tire air pressure does not exceed the air pressure target value. In some cases, the air release passage is blocked by a valve so that the tire air pressure is maintained at the air pressure target value.

  The transmitter 2 configured in this manner is housed in an air valve that is attached to a wheel hole of each of the wheels 5a to 5d, and is arranged so that the sensing unit 21 is exposed inside the tire. As a result, the corresponding tire pressure is detected, and a transmission frame is transmitted every predetermined period (for example, every minute) through the antenna 24 provided in each transmitter 2.

  The air filling device 7 is assembled in the wheel cap of each of the wheels 5a to 5d, generates compressed air by the rotational energy of the wheels 5a to 5d, and can fill the tire from the air valve into the tire through an air supply hose (not shown). It has become. Since this air filling device 7 is well known in the above-mentioned patent documents, it is omitted here.

  On the other hand, the receiver 3 includes an antenna 31 and a microcomputer 32 as shown in FIG.

  The number of antennas 31 corresponding to the number of tires, that is, the number of transmitters 2 is provided. Each antenna 31 is installed at a location corresponding to the position of each transmitter 2 in the vehicle body 6, and is fixed to the vehicle body 6 at a position spaced apart from each transmitter 2 by a predetermined distance, for example.

  The microcomputer 32 is composed of a well-known computer having a CPU, ROM, RAM, I / O, and the like. Specifically, the microcomputer 32 includes a wireless unit 32a, a control unit (second control unit) 32b, and the like, and performs predetermined processing according to a program stored in a memory (not shown) in the control unit 32b. It is supposed to run.

  The radio unit 32a functions as an input unit that receives a transmission frame from each transmitter 2 received by each antenna 31 and sends the transmission frame to the control unit 32b. The wireless unit 32a also functions as an output unit that outputs from the antenna 31 a signal indicating the tire air pressure setting value sent from the control unit 32b.

  The control unit 32b obtains the tire pressure by performing various signal processing and calculations based on the data indicating the detection result stored in the transmission frame sent from the wireless unit 32a, and responds to the obtained tire pressure. An electric signal is output to the display 4. For example, the control unit 32b compares the obtained tire air pressure with a predetermined threshold value Th, and when detecting that the tire air pressure has decreased, outputs a signal to that effect to the display 4. Yes. Thereby, the indicator 4 is informed that the tire pressure of any of the wheels 5a to 5d has decreased.

  In addition to the information related to the tire air pressure setting value manually input by the user, the control unit 32b includes a vehicle speed information detection unit 8a, a date / time (clock) information detection unit 8b, an outside air temperature detection unit 8c, a weather detection unit 8d, and road surface information. Various information and the like that may cause fluctuations in the appropriate tire pressure are input from the detection unit 8e and further from the occupant number detection unit 8f.

  For the information regarding the tire pressure setting value manually input by the user, for example, the tire pressure setting value or a selection associated with the tire pressure setting value is input by using the operation switch 4a for adjusting the tire pressure provided on the display unit 4 described later. When this is done, it is input to the control unit 32b as a signal corresponding to the selected content.

  The vehicle speed information detection unit 8a detects vehicle speed information of the vehicle 1, and is configured by a vehicle speed sensor or a wheel speed sensor (not shown), for example. The detection signal of the vehicle speed information detection unit 8a is input to the control unit 32b. Of course, when the vehicle speed has already been calculated based on the detection signal of the vehicle speed sensor or the wheel speed sensor in the other ECU provided in the vehicle 1, the ECU is used as the vehicle speed information detection means 8a, by in-vehicle communication, etc. Vehicle speed information may be input from the ECU to the control unit 32b.

  The date / time (clock) information detecting means 8b, the outside air temperature detecting means 8c, and the weather detecting means 8d each detect the date and time, the outside air temperature, or the weather, and output detection signals corresponding to these pieces of information to the control unit 32b. It is supposed to be. As these date / time (clock) information detecting means 8b, outside air temperature detecting means 8c, and weather detecting means 8d, when the vehicle 1 is originally provided with a system for obtaining such information, such systems are used. When the system is not provided in the vehicle 1, for example, a system that performs road-vehicle communication is used.

  The road surface information detection unit 8e detects road surface information such as a road surface friction coefficient, and is configured by a brake ECU or the like, and outputs a signal indicating road surface information to the control unit 32b using in-vehicle communication or the like. ing. That is, in the brake ECU, since the road surface μ and the like have already been obtained for ABS control or the like, a signal indicating this road surface information is output from the brake ECU.

  As shown in FIG. 4, the occupant number detection unit 8f detects the number of occupants seated on each seat in the passenger compartment, and outputs a detection signal corresponding to the number of occupants to the control unit 32b. It has become. For example, the occupant number detection unit 8f is configured by a load sensor attached to each seat, and by recognizing whether an occupant is seated on each seat based on a detection signal of each load sensor, The number of seated passengers is detected.

  Based on such information and the tire pressure data stored in the transmission frame sent from the transmitter 2, the control unit 32b obtains the tire pressure setting value of the vehicle 1 and then through the radio unit 32a. A signal indicating the tire pressure set value is transmitted to the transmitter 2 side.

  As shown in FIG. 1, the display 4 is arranged at a place where the driver can visually recognize, and is configured by an alarm lamp installed in an instrument panel in the vehicle 1, for example. For example, when a signal indicating that the tire air pressure has decreased is sent from the control unit 32b in the receiver 3, the display device 4 displays a message to that effect so as to notify the driver of the decrease in tire air pressure. It has become.

  The display 4 is provided with an operation switch 4a that can be operated by the user. When the user operates the operation switch 4a, the tire air pressure setting value or the selection content associated therewith can be manually input.

  The tire air pressure detection device is configured as described above.

  Next, the operation of the tire pressure detection device configured as described above will be described.

  First, at the time of normal tire pressure detection, the following operation is performed. That is, in the transmitter 2, data related to a detection signal indicating the tire air pressure or the temperature in the tire from the sensing unit 21 is input to the control unit 22 a. Then, after signal processing is performed as necessary, the signal is stored in a transmission frame and transmitted to the receiver 3 side through the radio unit 22b.

  On the other hand, when a transmission frame is transmitted from the transmitter 2, it is received by the antenna 31 of the receiver 3 and input to the control unit 32b through the radio unit 32a. Then, in the control unit 32b, data indicating the tire pressure and data indicating the temperature in the tire are extracted from the transmission frame, temperature correction is performed as necessary based on the data indicating the temperature, and the tire pressure is obtained. At this time, if it is determined that the determined tire pressure is below a predetermined threshold value, a signal indicating that is output from the control unit 32b to the display unit 4, and an alarm is given by the display unit 4. It is like that.

  In addition, the following operations are performed to adjust the tire pressure. This will be described with reference to FIGS.

  FIG. 5 is a flowchart of a tire air pressure set value transmission process executed by the control unit 32b on the receiver 3 side. First, the tire pressure set value transmission process executed by the control unit 32b on the receiver 3 side will be described with reference to this figure.

  First, in step 100, when the operation switch 4a is operated by the user and the tire pressure setting value Pset or the selection content associated therewith is input, the tire pressure setting value Pset requested by the user is read. That is, when the tire pressure setting value Pset is directly input as a numerical value by the user operating the operation switch 4a, the value is read. When the selection content associated with the tire pressure set value Pset is input, the associated tire pressure set value Pset is read.

  Note that the selection content associated with the tire pressure set value Pset here refers to the case where a plurality of switches such as a highway, a general road, a rainy road, and a frozen road are prepared as the operation switch 4a. This is the content indicated by the switch pressed. For example, 220 kPa when the highway switch is pressed, 200 kPa when the general road switch is pressed, 190 kPa when the rainy road switch is pressed, 180 kPa when the frozen road switch is pressed, etc. Since Pset is associated, the control unit 32b reads the tire pressure setting value Pset corresponding to the selection content indicated by the switch pressed by the user.

  In step 110, a signal indicating the tire air pressure set value Pset read in step 100 is sent to the radio unit 32a. As a result, a signal indicating the tire pressure set value Pset is transmitted to the transmitter 1 side via the antenna 31.

  On the other hand, the control unit 22a of the transmitter 1 receives the signal indicating the tire air pressure set value Pset transmitted from the receiver 3, thereby executing the tire air pressure adjusting process.

  FIG. 6 is a flowchart of the tire pressure adjustment process executed by the control unit 22a on the transmitter 2 side. With reference to this figure, the tire pressure adjusting process executed by the control unit 22a on the transmitter 2 side will be described.

  First, in step 200, a signal indicating the tire air pressure set value Pset transmitted from the receiver 3 is received, and the content is read. In step 210, the tire air pressure setting value Pset read in step 200 is stored as the air pressure target value.

  Subsequently, at step 220, the current tire pressure P0 is sensed. The tire air pressure P0 is obtained based on a detection signal related to the tire air pressure obtained by the sensing unit 21. For example, the tire air pressure (sensor value) P obtained by a pressure sensor is used. When the tire air pressure P0 is obtained in this way, it is determined in step 230 whether or not the tire air pressure P0 exceeds the air pressure target value (= Pset).

  If a negative determination is made in this step, it is assumed that the air is not overfilled, and the process is completed as it is. If an affirmative determination is made in this step, it is assumed that the air is overfilled and the routine proceeds to step 240, where a control signal (air release command signal is sent to drive the small actuator 24 to reduce the tire air pressure. ) Is output.

  Thereby, since the small actuator 24 is driven, the valve opens the air release passage and air is released. When the tire air pressure P0 decreases to the air pressure target value (= Pset) due to the release of air, a negative determination is made in step 230, so that the control signal (air release command signal) is not output, and the driving of the small actuator 24 is stopped. The air release passage is blocked by the valve, and the tire air pressure P0 is maintained at the air pressure target value (= Pset).

  Next, a tire air pressure set value determination process based on each information input to the control unit 32b will be described. FIG. 7 is a flowchart of the tire air pressure setting value determination process. This process is executed by the control unit 32b every predetermined calculation cycle.

  First, in step 300, it is determined whether or not the tire pressure setting value has been input by the user. This process is performed in order to preferentially set the tire pressure desired by the user even if there is an optimum pressure obtained from the above information. Therefore, if an affirmative determination is made in this step, the process proceeds to step 310, where the above-described input value by the user is set as the tire air pressure set value Pset that is transmitted to the transmitter 2 as it is.

  On the other hand, if a negative determination is made in step 300, the process proceeds to step 320, in which it is determined whether or not passenger number information is detected. This determination is made based on whether or not a detection signal is input from the occupant number information detection unit 8f. If a negative determination is made in this step, the normal manufacturer recommended pressure is registered as the first set value P1 in step 330. If an affirmative determination is made, it corresponds to the number of passengers detected in step 340. The manufacturer recommended pressure for each number of passengers is registered as the first set value P1. The first set value P1 here corresponds to the first provisional tire air pressure set value.

  In step 350, it is determined whether or not road surface information, weather information, outside air temperature information, and date / time (clock) information have been input. This determination is made based on whether or not a detection signal is input from the date / time (clock) information detection means 8b, the outside air temperature detection means 8c, the weather detection means 8d, and the road surface information detection means 8e.

  If a negative determination is made in this step, the first set value P1 is registered as the second set value P2 in step 360. If an affirmative determination is made in step 360, the road surface, weather, outside air temperature, The first set value P1 is corrected by an arithmetic expression using the date and time (clock) as a variable, and the corrected value is registered as the second set value P2. The second set value P2 here corresponds to a second temporary tire pressure set value.

  Next, in step 380, it is determined whether vehicle speed information has been input. This determination is made based on whether or not a detection signal is input from the vehicle speed detection unit 8a. If a negative determination is made in this step, the second set value P2 is directly registered as the tire air pressure set value Pset in step 390. If an affirmative determination is made, the vehicle speed Vt is used as a variable in step 395. The second set value P2 is corrected by the arithmetic expression, and the corrected value is registered as the tire air pressure set value Pset.

  When the tire air pressure set value Pset is determined in this way, a signal indicating the tire air pressure set value Pset is transmitted to the transmitter 2 side as in step 110 shown in FIG. The air pressure set value Pset is registered as the air pressure target value. Therefore, the tire air pressure is adjusted so as to be the air pressure target value.

  As described above, in the present embodiment, the tire 2 is filled with air through the air filling device 7, and when the tire air pressure exceeds the air pressure target value (= Pset), the transmitter 2 is provided. The valve is driven by the small actuator 24 so that air is discharged from the air release passage. The air pressure target value at this time can be changed according to variables such as the vehicle speed and road conditions in addition to the user's request.

  Therefore, the tire pressure can be adjusted by the transmitter 2 and the air filling device 7 provided in each of the wheels 5a to 5d, and a signal indicating the tire pressure set value Pset is sent from the receiver 3 to the transmitter 2. Just change the air pressure target value. Therefore, it is possible to provide a tire air pressure adjusting device that can change the air pressure target value according to variables such as the vehicle speed and road conditions in addition to the user's request and that can simplify the configuration.

(Second Embodiment)
A second embodiment of the present invention will be described. FIG. 8 shows a block configuration of the transmitter 2 in the tire pressure adjusting device of the present embodiment. Hereinafter, the tire pressure adjusting device of the present embodiment will be described. In the present embodiment, only the configuration of the transmitter 2 and the processing executed by the control unit 22a are changed with respect to the first embodiment. Since it is the same as that of 1st Embodiment, only a different part is demonstrated.

  As shown in FIG. 8, in the present embodiment, the transmitter 2 is provided with a gas generator 9 having an initiation device 9a and a gas generator 9b.

  The gas generator 9 is a device that instantaneously generates a large amount of gas in the gas generator 9b by a chemical reaction by energizing the detonator 9a. For example, it is known as an air filling technique in an airbag. It is what has been. When the gas generated by the gas generator 9 is filled in the tire, the tire air pressure can be restored at the time of puncture or the like. In addition, it is possible to include a filler for repairing puncture in the gas generated by the gas generator 9 and repair the puncture portion at the time of puncture.

  FIG. 9 is a flowchart of gas generation processing at the time of puncture executed by the control unit 22a provided in the transmitter 2 having the above configuration. This process is executed every predetermined calculation cycle.

  First, at step 400, the tire pressure P0 obtained at step 220 in FIG. 6 is read as the current tire pressure.

  In step 410, the value stored as the current tire pressure at the previous calculation cycle is set as the previous measured pressure Pm, and the difference (Pm−P0) between the previous measured pressure Pm and the current tire pressure P0 is obtained. It is determined whether or not a predetermined sudden pressure reduction threshold value Pd is exceeded. The sudden pressure reduction threshold value Pd here is set as a value that exceeds the value assumed to be normal natural air leakage as the amount of decrease in tire air pressure around the calculation cycle, and the previously measured pressure Pm. If the difference between the tire pressure P0 and the current tire pressure P0 (Pm−P0) exceeds the sudden pressure reduction threshold Pd, it is considered that the tire has been punctured.

  For this reason, if the determination in step 410 is negative, that is, it is determined that puncture has not occurred, the process proceeds to step 420 and the current tire pressure P0 obtained this time is substituted for the previous measured pressure Pm, thereby completing the process. .

  On the other hand, if the determination in step 410 is affirmative, that is, if it is determined to be punctured, the process proceeds to step 430 and the energization process for the detonator 9a is performed. Thereby, electricity supply is performed with respect to the initiation apparatus 9a, and a lot of gas is generated in the gas generator 9b.

  Subsequently, the process proceeds to step 440, where the same processing as in step 400 is performed again, and the tire pressure P0 after the energization of the detonator 9a is read. In step 450, processing similar to that in step 230 in FIG. 6 is performed. As a result, when the current tire pressure P0 exceeds the target air pressure value (= Pset), the routine proceeds to step 460, where the drive processing of the small actuator 24 is executed in the same manner as in step 240 in FIG. If not, the process is completed as it is.

  As described above, according to the present embodiment, the transmitter 2 includes the gas generation device 9, and a large amount of gas is generated from the gas generation device 9 at the time of puncture, whereby air supply to the tire is instantaneously performed. It is supposed to be. That is, at the time of puncture, since the speed of the air decrease amount due to puncture becomes faster than the air supply by the air filling device 7, the air supply is aided by using the gas generator 9. Thereby, it is possible to prevent the tire air pressure from rapidly decreasing at the time of puncture, and to prevent a tire burst due to a rapid decrease in the tire air pressure.

(Third embodiment)
In the first and second embodiments, the tire air pressure (sensor value) P detected by the pressure sensor provided in the sensing unit 21 is the tire air pressure P0, and the tire air pressure P0 becomes the air pressure target value (= Pset). A description has been given of such control. However, since the tire air pressure (sensor value) P detected by the pressure sensor provided in the sensing unit 21 is a value that does not take into account the temperature in the tire, the tire air pressure P0 is the air pressure target value (= Pset). ), The pressure will be as desired during driving, but in reality the air will be excessively removed due to the increase in temperature, and the vehicle will stop and the temperature in the tire will drop. Later, the tire pressure may be low.

  For this reason, the temperature rise in the tire during traveling is monitored by the control unit 32b on the receiver 3 side, and air is prevented from being excessively extracted with respect to the increase in air pressure due to the temperature rise based on Boyle Charles' law. To do.

  FIG. 10 is a flowchart of the air pressure target value correction process executed by the control unit 32b of the receiver 3 in the tire air pressure adjusting device of the present embodiment.

  First, in step 500, the tire pressure setting value Pset calculated by the control unit 32b in the tire pressure setting value determination process shown in FIG. 7 is set to Pset0. In step 510, the temperature Tt calculated by the temperature sensor is read from the transmission frame sent from the transmitter 2. Then, in step 520, assuming that the air pressure target value at a predetermined reference temperature (here, 25 ° C. is adopted) is Pset0, a value Pset1 when this air pressure target value is converted into temperature Tt is obtained. . This is obtained using the following equation based on Boyle-Charles' law.

(Equation 1)
Pset1 = P0 × (273 + Tt) / (273 + 25)
The air pressure target value Pset1 when converted to the temperature Tt thus obtained is updated as a new tire air pressure setting value Pset. This tire air pressure set value Pset is sent to the transmitter 2, and the transmitter 2 can adjust the tire air pressure based on the air pressure target value accompanying the temperature rise in the tire.

  Accordingly, it is possible to prevent the air from being excessively extracted due to the increase in air pressure due to the temperature rise, and it is possible to prevent the tire air pressure from being lowered after the vehicle stops and the temperature in the tire decreases.

(Other embodiments)
In the third embodiment, a case has been described in which the tire air pressure set value Pset is corrected as the temperature in the tire increases on the receiver 3 side, and the air pressure target value of the transmitter 2 is updated to a value corresponding to the temperature increase. . However, this is merely an example, and the same effects as in the third embodiment can be obtained even if other methods are used.

  For example, if an air pressure correction invalid signal instructing prohibition of air release is transmitted from the receiver 3 to the transmitter 2 and the air is prohibited from being released, the air is excessively removed by the increase in air pressure due to the temperature rise. Can be prevented.

  For this reason, the tire pressure when converted to a predetermined reference temperature (for example, 25 ° C.) is obtained based on the transmission frame from the transmitter 2 on the receiver 3 side, and the tire pressure exceeds the tire pressure set value Pset. If there is no air pressure correction invalid signal, the same effect as in the third embodiment can be obtained.

  Conversely, the same effect as described above can be obtained by the processing of the control unit 22a on the transmitter 2 side. That is, in the first embodiment, the tire air pressure (sensor value) P obtained by the pressure sensor is used as it is as the current tire air pressure P0, but the tire air pressure (sensor value) P obtained by the pressure sensor is used as the temperature sensor. The temperature correction pressure calculation may be performed so as to correct the temperature in the tire (sensor value) Tt obtained in (1).

  In the temperature correction pressure calculation, the tire air pressure P0 when converted into a predetermined reference temperature (here, 25 ° C.) is obtained in consideration of the fluctuation of the tire air pressure due to the influence of the vehicle running, the outside air temperature, and the like. The arithmetic expression at this time is expressed as follows, for example, based on Boyle Charles' law.

(Equation 2)
P0 = P × (273 + 25) / (273 + T)
In the above embodiment, the display 4 provided with the operation switch 4a has been described as an example. However, this is merely an example, and the display 4 may be configured separately.

  In the above embodiment, the tire pressure detection device in which the number of antennas 31 attached to the receiver 3 is arranged corresponding to each transmitter 2 has been described as an example. However, the tire pressure detection using the antenna 31 as one common antenna is described. The present invention can also be applied to an apparatus.

  Note that the steps shown in each figure correspond to means for executing various processes.

It is a figure showing the block composition of the tire air pressure detection device in a 1st embodiment of the present invention. (A) is a figure which shows the block configuration of the transmitter with which the tire pressure detection apparatus shown in FIG. 1 is equipped, (b) shows the block configuration of the receiver with which the tire pressure detection apparatus shown in FIG. 1 is equipped. FIG. It is a schematic diagram of a wheel provided with a transmitter and an air filling device. It is the schematic diagram which showed the mode of the passenger | crew number detection by a passenger | crew number detection part. It is a flowchart of the tire pressure setting value transmission process performed by the control unit on the receiver side. It is a flowchart of the tire pressure adjustment process performed by the control part by the side of a transmitter. It is a flowchart of a tire air pressure set value determination process. It is the figure which showed the block configuration of the transmitter of the tire pressure adjusting device shown in 2nd Embodiment of this invention. It is a flowchart of the gas generation process at the time of puncture. It is a flowchart of the air pressure target value correction process shown in the third embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Vehicle, 2 ... Transmitter, 3 ... Receiver, 4 ... Display, 4a ... Operation switch,
5a to 5d ... wheels, 6 ... vehicle body, 7 ... air filling device, 8a ... vehicle speed information detection unit,
8b ... Date and time information detection unit, 8c ... Outside air temperature detection unit, 8d ... Weather detection unit,
8e ... road surface information detection unit, 8f ... number of passengers detection unit, 9 ... gas generator, 9a ... detonator,
9b ... Gas generator, 21 ... Sensing unit, 22 ... Microcomputer,
23 ... Antenna, 22a ... Control unit (first control unit), 22b ... Radio unit (first radio unit),
24 ... small actuator, 31 ... antenna, 32 ... microcomputer,
32a ... Radio unit (second radio unit), 32b ... Control unit (second control unit).

Claims (5)

A sensing unit (21) that outputs a detection signal corresponding to the air pressure in the tire provided in each of the plurality of wheels (5a to 5d), and receives the detection signal of the sensing unit (21) to detect the tire air pressure. A first control unit (22a) that generates an air release command signal when the tire air pressure exceeds the air pressure target value, a first radio unit (22b) that receives radio waves, and the first control unit ( 22a) and a small actuator (24) that is driven based on the air release command signal generated to release air from the inside of the tire to the outside, and is provided in each of the plurality of wheels (5a to 5d). Transmitter (2),
A second control unit that is provided on the vehicle body (6) side, determines a tire air pressure setting value (Pset) of each of the plurality of wheels (5a to 5d), and outputs a signal indicating the tire air pressure setting value (Pset). (32b) and a receiver (3) including a second wireless unit (32a) that transmits radio waves toward the transmitter (2).
The first controller (22a) in the transmitter (2) receives a signal indicating the tire air pressure set value (Pset) output from the second controller (32b) in the receiver (3) as the second. When a radio wave is transmitted from the radio unit (32a), the first radio unit (22b) receives the radio wave, and the tire pressure set value (Pset) indicated in the radio wave is used as the air pressure target value. A tire pressure adjusting device characterized by being set. An operation switch (4a) for generating a signal indicating a tire pressure desired by the user or a signal associated with the tire pressure is provided, and the signal generated by the operation switch (4a) is generated in the receiver (3). Input to the second control unit (32b),
The second control unit (32b) is configured to determine a tire pressure desired by the user as the tire pressure set value (Pset) based on the signal generated by the operation switch (4a). The tire pressure adjusting device according to claim 1. The second control unit (32b) in the receiver (3) receives various information that can be a variation factor of the appropriate tire air pressure of each of the plurality of wheels (5a to 5d), and converts the various information that can be the variation factor. The tire pressure adjusting device according to claim 1, wherein the tire pressure setting value (Pset) is determined based on the tire pressure setting value (Pset). In the transmitter (2), the sensing unit (21) outputs a detection signal corresponding to the temperature in the tire, and the first control unit (22a) outputs the detection signal. The detection signal of the unit (21) is signal-processed and stored in a transmission frame, and further, the transmission frame is transmitted to the receiver (3) through the first wireless unit (22b).
In the receiver (3), the transmission frame is received through the second radio unit (32a) and transmitted to the second control unit (32b), and the second control unit (32b) converts the transmission frame into the transmission frame. The tire pressure set value (Pset) is corrected based on the stored detection signal corresponding to the temperature, and the corrected value is determined as the tire pressure set value (Pset). The tire pressure adjusting device according to any one of claims 1 to 3. In the transmitter (2), the sensing unit (21) outputs a detection signal related to the temperature in the tire, and the first control unit (22a) 21) process the detection signal and store it in a transmission frame, and further transmit the transmission frame to the receiver (3) through the first wireless unit (22b).
In the receiver (3), the transmission frame is received through the second radio unit (32a) and transmitted to the second control unit (32b), and the second control unit (32b) converts the transmission frame into the transmission frame. Based on the stored detection signal corresponding to the temperature, the tire air pressure of the plurality of wheels (5a to 5d) is obtained as a pressure when converted to a predetermined reference temperature, and this pressure is the tire air pressure set value (Pset). ), The air pressure correction invalid signal is transmitted from the second control unit (32b) through the second radio unit (32a), and the transmitter (2) drives the small actuator (24). The tire pressure adjusting device according to any one of claims 1 to 3, wherein the air release is prohibited.

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